Mary Lou Lee, age 13, of Vancouver, Wash., for her question:

HOW LONG IS A BOA CONSTRICTOR?

A boa constrictor is a large snake of the tropical parts of America.

It is not poisonous but kills animals for food by squeezing them with its long body. Most boa constrictors are about 10 feet long but they can grow to be 14 feet long.

Lots of people think the boa constrictor is the world's largest snake, but this isn't true. It is smaller than the anaconda of South America, the python of Asia, Africa and Australia and the king cobra of India.

Most boa constrictors live in the Guianas and in Brazil. Two smaller kinds live in the southwestern United States.

Boa constrictors cannot swallow horses or cows, as some people say, but they can swallow whole animals that are much larger than their heads because the bones of their jaws can be stretched far apart. This allows big things to pass into the throat and body, and these parts can also be stretched.

Boa constrictors hunt while hanging from trees. They attack animals that pass under them.

Boa constrictors do not lay eggs. They give birth to 50 live young snakes at one time.